Fisher challenged to play African-American man

The Australian star headed to the U.S. after her turn in 2002's Scooby-Doo in the hope of finding an agent to take her on.

Fisher was delighted when one agreed to represent her, despite not seeing any of the 33-year-old's movies.

But the beauty was left disheartened when she discovered the script he had in mind for her.

Fisher tells David Letterman, "When I first came to America I met one of the heads of a very important agency and he said to me, 'You are a talented actress'. I said 'What of my work have you seen?', and he said, 'Absolutely nothing. But I'm going to make you a star.'

"He said, 'There will be a script on your desk tomorrow', so I ran home and opened the script and it said, 'Isla Fisher, for your consideration: The role of Vivian'.

"I was so excited I flipped through the script and it said, 'The camera pans to Vivian. Vivian - a tall 45-year-old African-American man!' Clearly he thought I was a really good actress."